On Traken, the Master used a second TARDIS, disguised as a Melkur. Although this one was destroyed, he kept his grandfather clock TARDIS inside, and used it to escape after he stole the body of Tremas. (TV: The Keeper of Traken)

Over a decade would pass before the Master encountered a future, female incarnation who dubbed herself "Missy". Provided with a spare dematerialisation circuit by his future self, who had remembered to keep one as a result of this encounter, the Master proceeded to leave the ship in his TARDIS. However, before he left, Missy mortally wounded him in such a way as to force the Master's regeneration into her shortly after he reached his TARDIS. (TV: The Doctor Falls)

Missy implemented a plan involving travel through time to harvest recently deceased human minds for as long as humanity had a concept of the afterlife, the Twelfth Doctor theorized that she achieved this through use of a TARDIS. (TV: Death in Heaven)

The Master's TARDIS as displayed on Shada's internal computer. (COMIC: The One)

On Traken, the Master disguised a TARDIS as the Melkur. In this form, it was shown to be able to walk and could fire sonic beams from its eyes. When this TARDIS was destroyed, he fled in another he had kept in the former. This TARDIS was disguised as a grandfather clock. (TV: The Keeper of Traken)

The Master's TARDIS had a varied interior. Some interiors seemed to mimic the Doctor's re-designs of his own TARDIS at the time of the encounter. (TV: The Time Monster, Planet of Fire)

Much of the time, the interior was simply a sombre, black version of the interior of the Doctor's TARDIS, sometimes with special equipment such as the Hadron web which he used to hold Adric captive. (TV: Castrovalva)

Companions who spent time in the Master's TARDIS after spending time in the Doctor's ship noted that the atmosphere of the Master's TARDIS was far less welcoming than that of the Doctor's ship, as though both TARDISes had adapted to the moods of their owners. (PROSE: The Quantum Archangel)

Once, the Master tricked the Doctor into materialising his TARDIS around the Master's, creating a dimensionally recursive loop, (TV: Logopolis) repeating a situation that had previously occurred accidentally. (TV: The Time Monster)